The present invention relates generally to cleaning devices and more specifically to an improved fluid circuit for cleaning devices.
In the early prior art, the cleaning fluid was generally pre-mixed to the desired ratio of cleaning fluid to water and the only control provided was whether the cleaning fluid mixture was to be dispensed or not. In later developments, separate water sources and cleaning fluid sources were provided. They each generally included a valve at the bottom of the tank with operators to activate the valves to provide no cleaning fluid mixture, water alone, or water and cleaning fluid in a pre-set mixture as a function of the valves. A typical example of such a system is provided in U.S. Pat. No. 3,540,072. The systems generally could not control the mixture or the flow rate.
Another type of prior art system uses a source of water and uses an electric control solenoid to dispense the water and a source of cleaning fluid and a flow restriction at the outlet of the concentrated cleaning fluid source for adjusting the mixing ratio to the desired value. A typical example of this system is found in U.S. Pat. No. 3,940,826. These systems generally have the cleaning ratio set for the entire operation since the control is usually remote from the operator's handle.
Other prior art cleaning devices use a mixer which siphons cleaning fluid from a reservoir and introduces it into the water flow line with the force of the water projecting the mixture out onto the surface to be cleaned. A control knob is generally provided interior the housing to set the mixing ratio. A typical example of this kind of device is illustrated in U.S. Pat. No. 3,959,844.
Other cleaning devices use a gravity feed of droplets of pre-mixed cleaning fluid into a high pressure air stream to be directed onto the surface to be cleaned. A typical example is found in U.S. Pat. No. 2,986,764.
The gravity feed systems whether they be directly onto the surface or into an air flow do not provide appropriate control to assure proper mixture as well as uniform dispensing of the mixture.
An object of the present invention is to provide a fluid circuit which assures proper mixing of the cleaning fluid and water in a cleaning device.
Another object of the present invention is to provide a fluid circuit which assures proper mixture of a cleaning fluid and water and the dispensing of the fluid into an air stream.
Still another object of the present invention is to provide a fluid circuit which allows for inoperation control of the cleaning fluid to water mixing ratio.
These and other objects of the invention are attained by providing a pressurized source of water and a pressurized source of the cleaning fluid each connected respectively to separate inlets of a mixing device whose outlet is connected to a spray nozzle. The pressurized sources of water and cleaning fluid are a tank and a cartridge respectively which receive air pressure from a pump. The spray nozzle includes an air inlet as well as a mixed fluid inlet from the mixing means to project the mixed fluids onto the surface to be cleaned. An air pump provides not only the air inlet to the spray nozzle, but also to pressurize the water tank and fluid cartridge. The fluid circuit includes a first fitting connected to the outlet of the water tank and having a main outlet connected to the water inlet of the mixture and a second restricted outlet. A second fitting is connected to the restricted outlet and includes an inlet from the pressurized source of cleaning fluid and an outlet connected to the cleaning fluid inlet of the mixing device. When the water inlet to the mixing device is restricted to change the mixing ratio, water exits the first fitting into the second fitting through the restricted outlet to provide ultimately a mixture having a higher ratio of cleaning fluid to water at the outlet of the mixing device.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.